/**************************************************
 * dom-drag.js
 * 09.25.2001
 * www.youngpup.net
 * Script featured on Dynamic Drive (http://www.dynamicdrive.com) 12.08.2005
 **************************************************
 * 10.28.2001 - fixed minor bug where events
 * sometimes fired off the handle, not the root.
 **************************************************/

var Drag = {

 obj : null,

 init : function(o, oRoot, minX, maxX, minY, maxY, bSwapHorzRef, bSwapVertRef, fXMapper, fYMapper)
 {
  o.onmousedown = Drag.start;

  o.hmode   = bSwapHorzRef ? false : true ;
  o.vmode   = bSwapVertRef ? false : true ;

  o.root = oRoot && oRoot != null ? oRoot : o ;

  if (o.hmode  && isNaN(parseInt(o.root.style.left  ))) o.root.style.left   = "0px";
  if (o.vmode  && isNaN(parseInt(o.root.style.top   ))) o.root.style.top    = "0px";
  if (!o.hmode && isNaN(parseInt(o.root.style.right ))) o.root.style.right  = "0px";
  if (!o.vmode && isNaN(parseInt(o.root.style.bottom))) o.root.style.bottom = "0px";

  o.minX = typeof minX != 'undefined' ? minX : null;
  o.minY = typeof minY != 'undefined' ? minY : null;
  o.maxX = typeof maxX != 'undefined' ? maxX : null;
  o.maxY = typeof maxY != 'undefined' ? maxY : null;

  o.xMapper = fXMapper ? fXMapper : null;
  o.yMapper = fYMapper ? fYMapper : null;

  o.root.onDragStart = new Function();
  o.root.onDragEnd = new Function();
  o.root.onDrag  = new Function();
 },

 start : function(e)
 {
  var o = Drag.obj = this;
  e = Drag.fixE(e);
  var y = parseInt(o.vmode ? o.root.style.top  : o.root.style.bottom);
  var x = parseInt(o.hmode ? o.root.style.left : o.root.style.right );
  o.root.onDragStart(x, y);

  o.lastMouseX = e.clientX;
  o.lastMouseY = e.clientY;

  if (o.hmode) {
   if (o.minX != null) o.minMouseX = e.clientX - x + o.minX;
   if (o.maxX != null) o.maxMouseX = o.minMouseX + o.maxX - o.minX;
  } else {
   if (o.minX != null) o.maxMouseX = -o.minX + e.clientX + x;
   if (o.maxX != null) o.minMouseX = -o.maxX + e.clientX + x;
  }

  if (o.vmode) {
   if (o.minY != null) o.minMouseY = e.clientY - y + o.minY;
   if (o.maxY != null) o.maxMouseY = o.minMouseY + o.maxY - o.minY;
  } else {
   if (o.minY != null) o.maxMouseY = -o.minY + e.clientY + y;
   if (o.maxY != null) o.minMouseY = -o.maxY + e.clientY + y;
  }

  document.onmousemove = Drag.drag;
  document.onmouseup  = Drag.end;

  return false;
 },

 drag : function(e)
 {
  e = Drag.fixE(e);
  var o = Drag.obj;

  var ey = e.clientY;
  var ex = e.clientX;
  var y = parseInt(o.vmode ? o.root.style.top  : o.root.style.bottom);
  var x = parseInt(o.hmode ? o.root.style.left : o.root.style.right );
  var nx, ny;

  if (o.minX != null) ex = o.hmode ? Math.max(ex, o.minMouseX) : Math.min(ex, o.maxMouseX);
  if (o.maxX != null) ex = o.hmode ? Math.min(ex, o.maxMouseX) : Math.max(ex, o.minMouseX);
  if (o.minY != null) ey = o.vmode ? Math.max(ey, o.minMouseY) : Math.min(ey, o.maxMouseY);
  if (o.maxY != null) ey = o.vmode ? Math.min(ey, o.maxMouseY) : Math.max(ey, o.minMouseY);

  nx = x + ((ex - o.lastMouseX) * (o.hmode ? 1 : -1));
  ny = y + ((ey - o.lastMouseY) * (o.vmode ? 1 : -1));

  if (o.xMapper)  nx = o.xMapper(y)
  else if (o.yMapper) ny = o.yMapper(x)

  Drag.obj.root.style[o.hmode ? "left" : "right"] = nx + "px";
  Drag.obj.root.style[o.vmode ? "top" : "bottom"] = ny + "px";
  Drag.obj.lastMouseX = ex;
  Drag.obj.lastMouseY = ey;

  Drag.obj.root.onDrag(nx, ny);
  return false;
 },

 end : function()
 {
  document.onmousemove = null;
  document.onmouseup   = null;
  Drag.obj.root.onDragEnd( parseInt(Drag.obj.root.style[Drag.obj.hmode ? "left" : "right"]), 
         parseInt(Drag.obj.root.style[Drag.obj.vmode ? "top" : "bottom"]));
  Drag.obj = null;
 },

 fixE : function(e)
 {
  if (typeof e == 'undefined') e = window.event;
  if (typeof e.layerX == 'undefined') e.layerX = e.offsetX;
  if (typeof e.layerY == 'undefined') e.layerY = e.offsetY;
  return e;
 }
};

 

